• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.149-152
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• 2010

It was investigated that effect of the supersonic impulse turbine rotor leading edge thickness which was the part of 75 ton open cycle liquid rocket engine turbopump. The test for turbine was performed that the rotor thickness to pitch ratio was 1.9 and 1.4 to 30 ton turbine. As a result of test, the rotor with lower thickness(1.4) had 1.5% efficiency gain to the higher thickness(1.9) and the pressure ratio with maximum efficiency was increased to the nozzle full expansion point.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.29-37
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• 2015

This paper presents a numerical investigation on detonation of a kerosene-air mixture in the copper tube and the structural response associated with combustion instability in liquid rocket engine. A single step Arrehnius rate law and Johnson-Cook strength model are used to describe the chemical reaction of kerosene-air mixture detonation and the plastic deformation of the copper tube. The changes of flow field and tube stress which are induced by plastic deformation, are investigated on the different tube thicknesses and nozzle configurations.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.17-27
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• 2010

KSLV-I KM plume including alumina particle has been studied using the continuum solver. Alumina particles are assumed to have 7 different diameters, and the specific ratio of the plume gas is assumed to be 1.2, with which the internal nozzle flow characteristics are similar to those of the chemically equilibrium analysis results. The results showed that the expansion angle of the particles is smaller than that of the gas phase, and that the big sized alumina particles are gathered in the plume core and the expansion angles of the big sized particles are smaller than those of the light particles. When the emissivity of the particles are assumed to be 0.1, the radiative heat flux is equivalent to those measured during the flight test of KSLV-I.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.65-74
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• 2002

Optimal supersonic diffuser shape of integrated rocket ramjet engine was derived which maximizes the total pressure recovery. Mass flux is considered as a design constraint and the second oblique shock angle of the external ramp, the cowl-lip angle and the throat area are selected as design variables. Refined response surface method through design space transformation technique was developed and employed, and high confidence level of the regression model could be obtained. Genetic algorithm was implemented for both system optimizer and subspace regression model optimization. Virtual nozzle was located at the end of throat to adjust the back pressure. With only 20 aerodynamic analyses, optimal supersonic diffuser shape which has 14% improved total pressure recovery characteristics was successfully designed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.403-404
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• 2008

The 2nd stage Kick Motor under the national aerospace middle and long term plan operates over the height of 300Km. Rocket Motors, designed for operation in high altitude, need nozzles with large expansion ratio to improve thrust efficiency. Hence, to evaluate the performance of such rocket motors on the ground, similar low pressure with the operating condition has to be made for the ground test to prevent flow separation in the nozzle. This study is for the installation of the high altitude test facility and test result for Kick Motor.

• Carbon letters
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• v.4 no.3
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• pp.133-139
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• 2003

Carbon/carbon composites are ideal candidates for a number of aerospace applications including structural materials for advanced vehicles, leading edges, structures of re-entry and hypersonic vehicles and propulsion systems. One serious defect for such application of the carbon/carbon composites is their poor oxidation resistance in high temperature oxidizing environments. SiC coating was employed to protect the composites from oxidation. It is mechanically and chemically stable under extreme thermal and oxidative environments, provides good adhesion to the substrate, and offers good thermal shock resistance. The SiC layer on the nozzle machined from the carbon/carbon composites was formed by pack-cementation method. Then, erosion characteristic of SiC coated carbon/carbon nozzle was examined by combustion test using a liquid rocket motor. The erosion rates were measured as function of combustion pressure, ratio of oxygen to fuel, combustion time, density of the composites and geometry of reinforced carbon fibre in the composites. The morphology change of the composites after combustion test was investigated using SEM and erosion mechanism also was discussed.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.93-99
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• 2006

The effects of the changes of a film cooling mass flow rate and operating conditions on wall heat flux characteristics of a subscale calorimetric combustion chamber were investigated by experiment and numerical analysis. At the nominal operating condition, with the film cooling mass flow rate being 10.5 percent of a main fuel mass flow rate, maximum heat flux at the nozzle throat was measured to be 30 percent lower than that without the film cooling. For the relatively higher mixture ratio and chamber pressure condition, maximum heat flux at the nozzle throat was increased by 31 percent compared to that of the nominal condition test without film cooling.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.968-969
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• 2011

The characteristics of second throat exhaust diffuser were investigated by using CFD. Because the second throat exhaust diffuser(STED) is known as the effective device for simulating high-altitude circumstance more than a cylindrical supersonic diffuser STED was analyzed. The back pressure around nozzle was reduced by entrance size of STED and it was observed that the initial strong shock was the weak oblique shock along the diffuser. Therefore the static pressure at nozzle exit was recovered as the ambient pressure and the STED worked well.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.29-35
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• 2011

The behaviors of combustion-induced internal flows of SRM equipped with fin-slot grain and submerged nozzle are very complex and diverse. Cold air-flow tests for 2D and 3D scale models of SRM have been done in order to specify the visualization method to analyze particular internal flow patterns such as roll-torque inducing flow. Swirl flow induced by asymmetric vortical tubes also has been visualized through employing various light source and recording directions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.181-185
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• 2010

The behavior of combustion-induced internal flow of SRM equipped with fin-slot grain and submerged nozzle is very complex and diverse. Cold air-flow test for 2D and 3D scale models of SRM has been done in order to specify the visualization method to analyze particular internal flow patterns such as roll-torque inducing flow. Swirl flow induced by asymmetric vortical tube also has been visualized through employing various light source and recording directions.